Watching the British debate over Brexit one would be forgiven for regarding both sides of the argument as slightly hysterical. One side say that Brexit will destroy the British economy. The other that Brexit will unleash a new Elizabethan age, setting Britain free to sail off towards Asia.

You could spend months, as we probably will, arguing the details.

But for me, here’s the single biggest reason that Britain should remain.

The European room isn’t going away.

European integration is often painted in the UK (and Ireland) as a bit of a cult obsession, about building a superstate. There are, no doubt, some who believe in that goal, but that is not the reason why many moderate and mainstream continental office-holders continue to support the EU.

The first time I realised why continental Europe views European integration so differently was standing in a railway station in Paris, and seeing destinations on it that in Ireland you’d only see in an airport. It made me understand how on top of each other European countries actually are, and not just for trade, but shopping, work and school.

So many Europeans think nothing of crossing the border every day.

That mentality forces their elected leaders to work together. To respect each other’s workers and products. To want each other’s cars and trucks and drivers to obey the same laws. To want to ensure that other countries care for your people when they are visiting. To help each other’s police chase terrorists and sex traffickers across Europe.

These issues are all resolved in the European room, by ministers sitting and meeting and discussing and arguing and finally agreeing.

They will continue to be discussed post-Brexit and they will continue to affect Britain. Britain has been affected by events and decisions made in Europe for thousands of years, from the Vikings to Napoleon to Hitler. Why on Earth will that suddenly stop post-Brexit?

And here’s where it gets tricky: once the 27 members have decided a position, it becomes much more difficult for Britain from outside to get that position changed.

That’s not hyperbole, it’s simple logic. Imagine being a member of any club where one member refuses to attend meetings and then demands later that whatever everybody who attended the meeting decided be over turned. The rest simply won’t agree, especially not for a member who deliberately chose to vacate their place at the original meeting. British demands will require the other 27 countries still in the room to return to the room and carefully unpick agreed deals with each other to suit a country not in the room. Really? It’s like giving Canada a veto over anything decided in Westminster.

This is the issue at the heart of Brexit that eurosceptics choose to ignore. That there will be a place were most of Britain’s closest allies will meet and decide issues that affect Britain and Britain won’t be there.

It is, quite simply, odd.

If anyone advocated the same logic for NATO, the WTO, the WHO, the IMF, the G8 or the UN eyes would roll.

Eurosceptics keep pushing a vague idea that Britain will still somehow have some form of say over what the rest of Europe decides and debates. But that is also the logic for Britain withdrawing its ambassadors from across the world on the basis that “if it’s important I’m sure they’ll give us a call.”

Britain is important to the rest of Europe. But the idea that other countries in a room will put Britain’s interest ahead of their own is very courageous. Best case scenario will have British diplomats hanging around the wheelie bins outside the European Council building hoping to buttonhole the Swedish or Irish foreign minister to stop a directive that will inadvertently hurt Britain. This is how Britain sees itself? Hanging around the bins at summits?

Finally, on a non-technical point, how weird is it that Britain decides to walk off the pitch because it’s too hard and the other players are just too rough? The idea that Britain can handle the Chinese but not the Belgians? Please.

Britain has legitimate complaints about the EU. But if anything, it has been the hesitating by the door that has prevented the UK’s leaders from going full throttle in Brussels to get what Britain wants. Perhaps, after a clear yes, a British prime minister could go into the council without worrying about what the Daily Mail says and get a better deal? Just look at Commission President Jean-Claude Juncker. Britain was powerful enough to do a deal with France and Germany and block JCJ. But only if it had a serious candidate it would support. That’s the problem: even if David Cameron had nominated a serious British candidate the right-wing press would have called him a traitor rather than hailing it as a huge success. No serious candidate would have been insulting enough to the rest of Europe.

That’s the post-Brexit challenge: a British PM with a mandate to face down those who would sabotage Britain leading Europe.